Implement sha256 integrity checking and GPG file checking

[williamdes]

docker-phpmyadmin/Dockerfile

Line 56 in a42a6ec

"https://files.phpmyadmin.net/phpMyAdmin/${PHPMYADMIN_VERSION}/phpMyAdmin-${PHPMYADMIN_VERSION}-all-languages.tar.xz" && \

See: https://gist.github.com/williamdes/883f2158f17e9ed5a83d892ada56f5df#file-upgradephpmyadmin-sh-L96-L107
See: https://github.com/phpmyadmin/docker/blob/5.2.0/Dockerfile-alpine.template#L89-L103

[thespad]

Thanks, I'll take a look at this when I get a chance.